CHAPTER 7: STORING ORGANIZATION INFORMATION – DATABASES

·         DATABASE – maintains information about various types objects (inventory), events (transactions), people (employees), and places (warehouses).

·         Database models:

-          Hierarchical database model – information is organized into a tree-likes structure (using parent/child relationships) in such a way that it cannot have too many relationships.

-          Network database model – a flexible way of representing objects and their relationships.

-          Relational database model – stores information in the form of logically related two-dimensional tables.

·          ENTITY – a person, place, thing, transaction, or event about which is stored.

-          The rows in each table contain the entities.

·         ATTRIBUTES (FIELDS, COLUMNS) – characteristics or properties of an entity class.

-          The columns in each table contain the attributes.

KEYS AND RELATIONSHIPS

·         Primary key and foreign keys identify the various entity classes (tables) in the database.

-          Primary key – a field (or group of fields) that uniquely identifies a given entity in a table.

-          Foreign key – a primary key of one table that appears an attribute in another table and acts to provide a logical relationship among the two tables.

Relational Database Advantages

1.       Increased flexibility

·         A well designed database should:

-          Handle changes quickly and easily

-          Provide users with different views

-          Have only one physical view

o   Physical view – deals with the physical storage of information on a storage devise. Eg: hard disk.

-          Have multiple logical views

o   Logical view – focuses on how users logically access information.

-          Eg: a mail-order buss-2 people view diff format (logical views) but same physical view.

2.       Increased Scalability and performance

·         A database must scale to meet increased demand, while maintain acceptable performance levels

-          Scalability – refers to how well a system can adapt to increase demands.

-          Performance – measures how quickly a system performs a certain process or transaction.

3.       Reduced Information Redundancy

·         Database reduce information redundancy

-          Redundancy – the duplication of information or storing the information or storing the same information in multiple places

·         Inconsistency is one of the primary problem with redundant information-difficult to decide which is most current and most accurate.

4.       Increase Information Integrity (Quality)

·         Information integrity –measure the quality of information

·         Integrity constraint – rules that help ensure the quality of information

-          Relational integrity constraint – rule that enforces basic and fundamental information-based constrains

-          Eg: Users cannot create an order for nonexistent customer; An order cannot be shipped without an address

-          Business-critical integrity constrain – rule that enforce business rules vital to and organization’s success and often require more insight and knowledge that relational integrity constraint.

-          Eg: product returns are not accepted for fresh product 15 days after purchase; A discount maximum of 20 percent.

5.       Increased Information Security  

·         Information is an organizational asset and must be protected

·         Databases an offer several security features including:

-          Password – provides authentication of the user

-          Access level – determines who has access to the different types of information

-          Access control – determines types of user access, such as read-only access

DATABASE MANAGEMENT SYSTEM

·         Database management system (DBMS) – software through which users and application programs interact with a database.

DATA-DRIVEN WEB SITES

·         An internet web site kept constantly updated and relevant to the needs of its customers through the use of a database.

Data-driven website advantages:

§  Easy to manage content: website owners can make changes without relying on MIS professional; user can update a data-driven website with little or no training.

§  Easy to store large amount of data: Data-driven websites can keep large volumes of information organized. Website owners can use templates to implement changes for layouts, navigation, or website stricter. This improves website reliability, scalability, and performance.

§  Easy to eliminate human errors: Data- driven websites trap data-entry errors, eliminating inconsistencies while ensuring all information is entered correctly.

DATA-DRIVEN BUSINESS INTELLIGENCE

·         BI in a data Web site

Integrating Information among Multiple Databases

·        Integration – allows separate systems to communication directly with each other

-         Forward integration – takes information entered into a given system and send it automatically to all downstream systems and processes

-         Backward integration – take information entered into a given system and sends it automatically to all upstream systems and processes

·         Building a central repository specifically for integrated information

·         Without integration, an organization will:

-          Spend considerable time entering the same info in multiple system

-          Suffer from the low quality and inconsistency typically embedded in redundant info

-          Poor information can produced poor decision